CHROMIUM: gpu: mali: GPUCORE-48377 Avoid reclaiming hoarded heap head chunk

BUG=b:536947554
UPSTREAM-TASK=b:260376782
TEST=CQ

Change-Id: I53e35c2f96e319edeb6576de274c65363570c004
Signed-off-by: Dominik Behr <dbehr@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/8501919
Tested-by: Dominik Behr <dbehr@chromium.org>
Reviewed-by: Suleiman Souhlal <suleiman@google.com>
Auto-Submit: Dominik Behr <dbehr@chromium.org>
Commit-Queue: Suleiman Souhlal <suleiman@google.com>
Reviewed-by: Yiwei Zhang <zzyiwei@google.com>